Huge rocket assisted projectile

[wichitaslumlord]

The person I got this from said it was an experimental rocket assisted projectile tested by the U.S. Navy at the Aberdeen proving ground. It measures 7 3/16 (18.3cm) in diameter, 36 3/8 (92.5cm) long ogive to base, 38 3/8 (97.5cm) long ogive to tip of nozzles. He said that the fuze did not come with it. The nozzles are canted so as to provide a rotational stabilization. there is no rotating band. One picture has it next to a U.S. 7.2 Chemical rocket to give an idea of its size. Any help in identifying it would be greatly appreciated! THANKS! Pat

 

[HAZORD]

Thanks for posting the photos. Both items are very interesting. Are there any letters or numbers stamped into the metal of the motor or warhead?

Your mystery piece is most likely an experimental rocket. The U.S. didn't have a gun in 7 3/16" caliber for one. If it was gun fired, it would have a rotating band. The rocket nozzels are too canted for a gun launched projectile. They are canted to give it the spin stability it needs. Rocket assisted projectiles have less motor to warhead size ratio, and almost all designs use only one nozzel in the center of the motor, to include the 105 Howitzer, 155mm Howitzer and 8 inch howitzer. Rockets are notoriously inaccurate. Rocket assisted projectiles are also inaccurate, but they at least carry a heavy frag warhead with a great deal of explosive, to a long distance. Neither the Army or Navy would tie up a high pressure gun tube to launch a rocket that could be launched out of a piece of pipe.

 

[US-Subs]

Pat,
I think I've got some paperwork on experimental rockets at home. Most of this was a little later, 50s and 60s stuff, but there might be something on your piece as well. If I were guessing, I would say it was intended as an upgrade to the 7.2-inch rocket. By the end of the War they were playing with a lot of rocket stuff, and 7.2 and 11 inch seemed to be a couple of the favorite sizes. I know that the 7.2 was being experimented with on shallow water boats and landing craft, but as an Army system. Most of what I've seen on it was in reports about testing in Panama, and that was mostly testing of your chemical piece and related items.

I should be home late March, give me a call to remind me and I'll do some digging and see if I can find anything.

Do you have any stamped markings on your CW piece? Looks like the T21 or M25. I'm just finishing up the update on Pre-46 chemical weapons and I'd like to include it, the only previous one I've found to photograph was a live one in Panama and it was in pretty rough shape.

 

[US-Subs]

Pat here is an experimental 7.2-inch I've got at the house; the T14. I haven't put much effort into researching it yet (someday when I have the time) but it seems further along the development path than your CW piece, but not so far as the piece you are questioning. I have no idea how the T14 was stabilised, it had to have some sort of fin assembly. It seems like I've got an OP somewhere that identifies some of the T-type 7.2s, if I get a few minutes this weekend I'll see if I can dig something out.

 

[wichitaslumlord]

Thanks to HAZORD and US-Subs for their input. What you say makes perfect sense. There are no stamped markings on the main item in question except for the one seen in the photo of the concave plate that forms the top of the motor compartment. I will have to look the 7.2 chemical rocket over more closely. Thanks again for the information! Pat

 

[US-Subs]

Thanks for posting the photos. Both items are very interesting. Are there any letters or numbers stamped into the metal of the motor or warhead?

Your mystery piece is most likely an experimental rocket. The U.S. didn't have a gun in 7 3/16" caliber for one. If it was gun fired, it would have a rotating band. The rocket nozzels are too canted for a gun launched projectile. They are canted to give it the spin stability it needs. Rocket assisted projectiles have less motor to warhead size ratio, and almost all designs use only one nozzel in the center of the motor, to include the 105 Howitzer, 155mm Howitzer and 8 inch howitzer. Rockets are notoriously inaccurate. Rocket assisted projectiles are also inaccurate, but they at least carry a heavy frag warhead with a great deal of explosive, to a long distance. Neither the Army or Navy would tie up a high pressure gun tube to launch a rocket that could be launched out of a piece of pipe.

John, thought I'd offer this exception to the rule of single nozzles (as you said, almost all). Here is a shot from the basement, a US 4.2-inch mortar, rocket assist with two nozzles. It is stamped with XM, but no model number.

 

[HAZORD]

Jeff,

Nice bullet! Yes, thanks for reminding me of that one. I was actually thinking about the 115mm Marine Corps Rocket you posted a couple of weeks back. I have a couple of the rocket assisted 4.2s, an illum and an HE. From a design point of view, a mortar round would need symmetrical nozzels off center around the perifery due to the propulsion initiator being in the middle.

 

[US-Subs]

The French solved it differently. Their initiator dropped away and the nozzle was single and center. The second of these 120mm PEPA types is a cut-away showing the motor, but I don't have a picture with me.

 

[HAZORD]

I haven't ever had the chance to lay hands on one of those for observation or posession. Nice bullets!